William Smith's 1815 geological map: 'A delineation of the strata of England and Wales with part of Scotland ...'

'The principles of geology like those of geometry must begin at a point, through two or more of which the geometrician draws a line and by thus proceeding from point to point, and from line to line, he constructs a map, and so proceeding from local to general maps, and finally to a map of the world. Geometricians founded the science of geography, on which is based that of geology' (William Smith, 1839, quoted in Cox, 1942, p. 64).